De link
% bl0ck_qu0te%e
% bl0ck_qu0te%sudo -i
mkdir /mnt/recovery
mount -o loop /media/xubuntu/Data/ubuntu/disks/root.disk /mnt/recovery
apt-get install vim
vim /mnt/recovery/boot/grub/grub.cfg # set "ro" flags to "rw" as per Daniel's comment (#8 above)
vim /mnt/recovery/etc/grub.d/10_linux # change "ro" to "rw" as above
reboot